In a flat panel display, a TFT, which is a three-terminal element, is used as the switching element. A gate line transfers a scanning signal for controlling the thin film transistor, a data line transfers a data signal applied to a pixel electrode, as well as other elements are included in the flat panel display. To provide better color accuracy and display response time, a high-performance TFT is needed in a panel display. Therefore, there is room for improvement in the art.